Compressor with cartridge assembly

ABSTRACT

The invention relates to a vane type compressor comprising a tubular body having inlet and outlet ports, end plates closing the ends of said tubular body, a rotor supported for rotation in said tubular body and sliding vanes supported by said rotor, one of said end plates being axially retained with said rotor and axially displaceable relative to said tubular body.

United States Patent [191 Schmitz [11] 3,826,597 July 30,1974

[ COMPRESSOR WITH CARTRIDGE ASSEMBLY [75] Inventor: Lothar Peter Schmitz, Pudsey, near Leeds, England [73] Assignee: The Drum Engineering Co.,Limited,

Dudley Hill, Bradford, England 22 Filed: Oct. 19,1972 2] App]. No.: 299,064

[52] US. Cl 418/131, 418/270, 29/1564 R [51] Int. Cl. F0lc 19/08, F04c 15/00, F04c 27/00 [58] Field of Search 418/70, 107,131, 134, 418/266-268, 270; 29/1564 R [56] References Cited UNITED STATES PATENTS 1,854,692 4/1932 Cooper 418/134 1,994,786 3/1935 Redfield 418/134 2,717,770 9/1955 Gibson et a1. 3,734,652 5/1973 Barnett 418/70 Primary Examiner-Carlton R. Croyle Assistant Examiner-John J. Vrablik Attorney, Agent, or Firm-Diller, Brown, Ramik & Wight [5 7] ABSTRACT The invention relates to a vane type compressor comprising a tubular body having inlet and outlet ports, end plates closing the ends of said tubular body, a rotor supported for rotation in said tubular body and sliding vanes supported by said rotor, one of said end plates being axially retained with said rotor and axially displaceable relative to said tubular body.

8 Claims, 2 Drawing lFigures PATENTEDJUBOIHH 3.826.597

SHEET 2 OF 2 COMPRESSOR WITH CARTRIDGE ASSEMBLY The-present invention relates to compressors and has particular application to vane-type compressors.

Vane-type compressors are known and comprise a tubular body within which a rotor, having radially slidable vanes, is arranged for rotation about an axis offset from the axis of the tubular body. Openings in opposite sides of the tubular body define inlet and outlet ports for the compressor dependent upon the direction of rotation of the rotor.

The ends of the tubular body are closed by end plates secured to the ends of the body and the fixed end plates support the bearing assemblies for the rotor. Difficulties exist with the above described conventional vanetype compressors in that very fine clearances between the rotor and faces and the end plates are essential for efficient performance of the compressor. An axial expansion of the rotor relative to the tubular body can cause damage to the rotor end faces and end plates whilst an axial expansion of the housing relative to the rotor will cause an increased clearance between the rotor and end plates, with a resulting loss of efficiency of the compressor.

The object of the present invention is to provide a construction for a vane-type compressor.

According to the present invention a vane-type compressor comprises a tubular body having inlet and outlet ports, end plates closing the ends of the tubular body and a rotor, provided with radially sliding vanes, rotatably mounted within the tubular body, one of said end plates being axially restrained with the rotor and adapted for axial displacement relative to the tubular body.

Preferably each end plate has a bearing block secured thereto and each bearing block is in sliding, fluidtight engagement with the bore of the body. Conveniently each bearing block supports bearings for the rotor shaft.

Preferably both end plates and theirrespective hearing blocks and associated bearings are arranged for axial displacement relative to the tubular body.

The, or each, axially displaceable end plate and its associated bearing block and bearings is preferably restrained against rotational displacement relative to the tubular body by pegs disposed parallel to the axis of the rotor and conveniently said pegs may be secured in the tubular body and slidably disposed in bores in the end plates.

Preferably the bearing blocks are secured to the end plates by bolts, and the bearings for the rotor comprise ball races which engage an internal radial shoulder within the bearing block and are urged against said shoulder by an annular part of the associated end plate.

The invention will now be described further by way of example with reference to the accompanying drawings, in which:

FIG. 1 shows a section through a vane-type compressor, in accordance with the invention, on the line II of FIG. 2; and

FIG. 2 shows a section through the rotor on the line lI-Il of FIG. 1.

In the illustrated example a vane-type compressor comprises a tubular body 11 within which a rotor as sembly, comprising a shaft 12, rotor body 13 and six equally spaced radial vanes 14, is disposed. Each radial vane 14 is slidablydisposed in a radial slot 13a in rotor body 13, the length of each of the sliding vanes l 4 is exactly equal to the length of the rotor body 13 and the length of rotor body 13 is less than the axial length of the tubular body 11. y

A bearing block 15 is slidably inserted into one end of the bore of the body 11 and has a peripheral recess 16 within which an annular sealing member 17 is disposed to providea fluid-tight sliding seal between bearing block 15 and the bore of the tubular body 11. The shaft 12 passes axially through the bearing block 15 and is rotatably supported by a ball race 18 located in an enlarged bore region 19 of the block 15. The ball race 18 comprises an outer ring 18a which abuts an annular shoulder 20 defining the inner end of the enlarged bore region 19, an inner ring 18b tightly fitting on shaft 12, and balls 18c adapted to roll between the rings 18a and 18b.

An end plate 21 is secured to the bearing block 15 by screws 22 and presents an axially extending boss portion 21a which enters into the enlarged bore 19 of bearing block 15 to sandwich the outer ring 18a of the bearing 18 against the annular shoulder 20. With this arrangement the bearing block 15, end plate 21 and bearing 18, comprise a'rigidly connected end assembly.

An axial sleeve 23, screwed on to shaft 12, retains the inner ring 18b of bearing 18 against a spacer member 24, which spaces ring 18b from'the rotor 13, and a fluid seal 25, housed in a recess 26 in end plate 21, provides a fluid-tight sliding seal between the end plate 21 and the sleeve 23.

The end plate 21, is connected to the tubular body 11 only by pegs 27 each of which pegs 27 is secured in a bore 28 in the end face of tubular body 11 and extends axially parallel to the tubular body 11 into an aligned bore 29 in end plate 21. Each pin 27 is a sliding fit in its associated bore 29 and thus end plate 21 and the assembly 15, 18a secured therewith is restrained against rotational but not axial displacement with respect to the tubular body 11.

The other end of the tubular body 11 is closed by an identical but diametrically opposite, end closure assembly and this assembly thus comprises a bearing block 15', peripherally sealed with the bore of tubular body 11 by a sealed member 17, an end plate 21' attached to the block 15' by screws 22 and a bearing 18 rotatably supporting shaft 12. The end plate 22' is restrained against angular displacement relative to the tubular body 11 by pegs 27 slidably disposed in bores 29 in the end plate 21.

It will be noted from FIG. 2 that the rotational axis of the shaft 12 is offset from the axis of the tubular body 11 so that a crescent-shaped space exists between the rotor 13 and the bore of tubular body 11. In operation anti-clockwise rotation of the rotor 13 (as viewed in FIG. 2) causes the outer end faces of the vanes 14 to maintain a continuous sliding contact with the bore of the tubular body 11 whereby fluid flowing through an inlet opening 30 into the tubular body 11 is conveyed in the spaces between the vanes 14 through the crescent-shaped space to an outlet exhaust opening 31 in the tubular body. 11. As the fluid flows into one side of the crescent space where the volume between the vanes is increasing and is released at the other side of the crescent space where the volume between the vanes 14is reducing the fluid is released at outlet 31 at a higher pressure than the pressure at inlet opening 30.

With the construction proposed by the present invention, the inner rings 18b, 18b are always positively located relative to rotor 13 by their respective spacers 24, 24' and sleeves 23, 23' and the axial positions of bearing blocks 15, 15 is determined by the axial positions of the bearings 18, 18' so that a predetermined fixed clearance between the end faces of the rotor 13 and bearing blocks 15, 15 is obtained. Differential axial expansion of the assembly within the tubular body 11 relative to the body 11 is accommodated by axial displacement of the end plates 21 and 21 relative to the tubular body 11 on their respective pins 27 and 27 and this does not induce any axial stress between body 11 and the internal assembly.

The present invention thus proposes a construction in which differential axial expansion between the tubular body lll and the remaining parts of the compressor is accommodated by an axial sliding action between the body 11 and the end plates 21, 21 without affecting the predetermined fixed clearance between the bearing blocks 15, 15 and the rotor 13.

In the construction described above the spacers 241, 24 bearings 18, 18, bearing blocks 15, 15' sleeves 23, 23, seals 17, 17' and 25, 25 and end plates 21, 21' can be assembled together with the shaft 12, the rotor 13 and the vanes 14 to form a compressor cartridge for a tubular body. To remove a cartridge from a compressor it is only necessary to release one end plate 21 or 21', by removing the retaining bolts 22 or 22, and the en tire cartridge can then be withdrawn. To insert a car tridge one end plate 21 or 21' is removed from the assembly, the assembly is inserted into the tubular body and the end plate fitted thereto.

The construction thus allows the cartridge to. be removed forinspection or replacement so that when the compressor is in an installation down times is reduced to a few minutes and the cartridge displacement is effected without interference with the connections between the tubular body and the installation.

Further, the preassembly of the cartridge allows the rotor and the end assemblies to be set up, inspected and tested before being installed in a tubular body. The clearances between the rotor end faces and the bearing blocks can be adjusted, by interchanging spacers 24, until the desired clearance is obtained, and the assembly locked by grub screws 23a, 23a, in threaded bores in sleeves 23, 23 respectively, engageable with the rotor shaft 12 to prevent accidental rotation of the sleeves 23, 23 relative to the shaft 12.

I claim:

1. A vane type compressor comprising a tubular body having inlet and outlet ports and ends, a rotor assembly mounted for rotation within said tubular body about an axis parallel to the axis of said tubular body, said rotor assembly comprising a rotor body with shaft ends extending axially therefrom and sliding vanes supported in slots in said rotor body, two end assemblies identically constructed but assembled in diametrically opposite order, said end assemblies closing their respective rotor shaft ends, said end assemblies being both axially located with respect to their respective shaft ends and restrained against axial displacement relative thereto, means mounting each end assembly with respect to said tubular body for relative axial movement with movement of each end assembly away from said tubular body being restricted only by the other of the end assemblies, whereby said rotor assembly and said axially attached end assemblies are axially displaceable relative to said tubular body, and means for preventing rel ative rotation between said end assemblies and said tubular body, each end assembly including a bearing block slidably disposed within the respective end of said tubular body, and an end plate axially outwardly of the bearing block and presenting a radial surface axially aligned with a radial surface of the tubular body for engagement therewith to limit both the entry of the respective end assembly into said tubular body and movement of the other of said end assemblies out of said tubular body, means removably securing at least one of said end plates to its respective bearing blocks whereby said rotor assembly and said end assemblies are removable from said tubular body as a unit upon removal of said one end plate.

2. A vane type compressor according to claim 1 and wherein each end assembly includes roller bearings for rotatably supporting its respective rotor shaft end.

3. A vane type compressor according to claim 1 in which said means for preventing relative rotation between said end assemblies and said tubular body comprise guide pins secured to the tubular body and extending substantially parallel to the axis of the tubular body into sliding engagement with bores in said end assemblies.

4. A vane type compressor according to claim 1 and wherein a spacer ring is provided between each end assembly and the face of the rotor body adjacent thereto.

5. A vane type compressor according to claim 1 and wherein each end assembly includes a sleeve secured on the rotor shaft.

6. A vane type compressor according to claim 1 and wherein each assembly also includes a bearing having radially inner and outer rings, said bearing block supporting said outer ring and limiting axial inward movement thereof, said end plate having a part axially engaging said outer ring for retaining the said outer ring with the bearing block, and a sleeve axially engaged with said inner ring and having a screw threaded part engaged with a screw threaded part on its associated rotor shaft end, and means for locking the said sleeve to the rotor shaft against relative rotation.

7. A vane type compressor according to claim 6 wherein each end plate is slidably mounted on a respective sleeve in sealed relation thereto.

8. A vane type compressor according to claim 6 and wherein a spacer ring is provided between each bearing inner ring and the end face of the rotor body adjacent thereto to space the respective bearing block from the adjacent end face of the rotor body.

a s: s 

1. A vane type compressor comprising a tubular body having inlet and outlet ports and ends, a rotor assembly mounted for rotation within said tubular body about an axis parallel to the axis of said tubular body, said rotor assembly comprising a rotor body with shaft ends extending axially therefrom and sliding vanes supported in slots in said rotor body, two end assemblies identically constructed but assembled in diametrically opposite order, said end assemblies closing their respective rotor shaft ends, said end assemblies being both axially located with respect to their respective shaft ends and restrained against axial displacement relative thereto, means mounting each end assembly with respect to said tubular body for relative axial movement with movement of each end assembly away from said tubular body being restricted only by the other of the end assemblies, whereby said rotor assembly and said axially attached end assemblies are axially displaceable relative to said tubular body, and means for preventing relative rotation between said end assemblies and said tubular body, each end assembly including a bearing block slidably disposed within the respective end of said tubular body, and an end plate axially outwardly of the bearing block and presenting a radial surface axially aligned with a radial surface of the tubular body for engagement therewith to limit both the entry of the respective end assembly into said tubular body and movement of the other of said end assemblies out of said tubular body, means removably securing at least one of Said end plates to its respective bearing blocks whereby said rotor assembly and said end assemblies are removable from said tubular body as a unit upon removal of said one end plate.
 2. A vane type compressor according to claim 1 and wherein each end assembly includes roller bearings for rotatably supporting its respective rotor shaft end.
 3. A vane type compressor according to claim 1 in which said means for preventing relative rotation between said end assemblies and said tubular body comprise guide pins secured to the tubular body and extending substantially parallel to the axis of the tubular body into sliding engagement with bores in said end assemblies.
 4. A vane type compressor according to claim 1 and wherein a spacer ring is provided between each end assembly and the face of the rotor body adjacent thereto.
 5. A vane type compressor according to claim 1 and wherein each end assembly includes a sleeve secured on the rotor shaft.
 6. A vane type compressor according to claim 1 and wherein each assembly also includes a bearing having radially inner and outer rings, said bearing block supporting said outer ring and limiting axial inward movement thereof, said end plate having a part axially engaging said outer ring for retaining the said outer ring with the bearing block, and a sleeve axially engaged with said inner ring and having a screw threaded part engaged with a screw threaded part on its associated rotor shaft end, and means for locking the said sleeve to the rotor shaft against relative rotation.
 7. A vane type compressor according to claim 6 wherein each end plate is slidably mounted on a respective sleeve in sealed relation thereto.
 8. A vane type compressor according to claim 6 and wherein a spacer ring is provided between each bearing inner ring and the end face of the rotor body adjacent thereto to space the respective bearing block from the adjacent end face of the rotor body. 